Plastic material preforms and containers blow molded from such preforms are well known. It is also well known to form preforms of a multilayer construction which may include one or more barrier layers. Such preforms and modes of making the same are disclosed, for example, in the patent to Krishnakumar et al. U.S. Pat. Nos. 4,609,516 granted Sept. 2, 1986 and Beck 4,550,043 granted Oct. 29, 1985. Further, it is known to provide apparatus for the injection molding of preforms wherein there are provided a plurality of metering pots and an injection nozzle which is provided with a plurality of coaxial flow passages, each nozzle passage having a separate gate controlled by a common gate pin.